s390/mm: cleanup phys_to_pfn() and friends

#define __pa(x)			((unsigned long)(x))

#define __va(x)			((void *)(unsigned long)(x))

#define virt_to_pfn(kaddr)	(__pa(kaddr) >> PAGE_SHIFT)

#define pfn_to_virt(pfn)	__va((pfn) << PAGE_SHIFT)

#define phys_to_pfn(phys)	((phys) >> PAGE_SHIFT)

#define pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)

#define phys_to_page(phys)	pfn_to_page(phys_to_pfn(phys))

#define page_to_phys(page)	pfn_to_phys(page_to_pfn(page))

#define pfn_to_virt(pfn)	__va(pfn_to_phys(pfn))

#define virt_to_pfn(kaddr)	(phys_to_pfn(__pa(kaddr)))

#define pfn_to_kaddr(pfn)	pfn_to_virt(pfn)

#define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))

#define page_to_virt(page)	pfn_to_virt(page_to_pfn(page))

#define phys_to_pfn(kaddr)	((kaddr) >> PAGE_SHIFT)

#define pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)

#define phys_to_page(kaddr)	pfn_to_page(phys_to_pfn(kaddr))

#define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)

#define virt_addr_valid(kaddr)	pfn_valid(__pa(kaddr) >> PAGE_SHIFT)

#define virt_addr_valid(kaddr)	pfn_valid(virt_to_pfn(kaddr))

#define VM_DATA_DEFAULT_FLAGS	(VM_READ | VM_WRITE | \

				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)